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LIBRARY OF THE 

UNIVERSITY OF ILLINOIS 

AT URBANA-CHAMPAIGN 



590.5 
FI 

v. 44 
cop. 3 




NArURAL HISTORY. 
SURVFY 



J 



iff. s 

|f. 5 FIELDIANA ZOOLOGY 

Published by 
CHICAGO NATURAL HISTORY MUSEUM 

Volume 44 November 28, 1961 No. 5 






A New Colubrid Snake of the Genus 
Pseudorabdion from Sumatra 

Robert F. Inger 
Curator, Division of Amphibians and Reptiles 

AND 

Alan E. Leviton 

Department of Herpetology, California Academy of Sciences 

Recently the Naturhistorisches Museum of Vienna sent a collec- 
tion of Indo-Malayan snakes to Chicago Natural History Museum in 
connection with a study being carried out by the senior author. This 
collection includes a single specimen of a new species of the genus 
Pseudorabdion. We are grateful to Dr. J. Eiselt of the Naturhis- 
torisches Museum for permission to describe this species, which we 
are naming after him. 

Pseudorabdion eiselt i, new species. Figure 13. 

Holotype. Naturhistorisches Museum number 16806, a gravid 
female from Padang, Sumatra, collected by J. Schild, 1899. 

Diagnosis. No preocular or loreal shields; postocular and supra- 
ocular shields not fused together or to the ocular shield; frontal 
separated from eye by supraocular; nasal small, undivided; inter- 
nasal touches first two supralabials. 

Description of holotype. Rostral as high as wide, portion visible 
from above equal to length of internasal suture; internasal small, 
greatest length about half that of prefrontal; internasal touches first 
and second supralabials; prefrontal three-fourths of length of frontal, 
touches second and third supralabials and eye; supraocular distinct 
from postocular, about one-third of width of frontal; frontal hexag- 
onal, separated from orbit, two-thirds of length of parietal; length of 
parietal equal to its distance from tip of snout; nasal undivided, 
small, not covering entire dorsal edge of first supralabial; no loreal 
or preocular; postocular not as high as eye; diameter of eye equal to 

Library of Congress Catalog Card Number: 61-1869U 
No. 940 Tiw ,,^ 45 

THE LIBRARY CF THE 

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46 FIELDIANA: ZOOLOGY, VOLUME 44 

vertical distance from eye to mouth; five supralabials and a large 
postlabial scale; supralabials increasing in size posteriorly, the fifth 
much the largest, the third and fourth bordering the eye; fifth labial 
broadly in contact with parietal; a large scale between the post- 
labial and parietal; mental touches anterior chin shields; five infra- 
labials, the first three touching the anterior chin shields; a gular 
scale partly separates the posterior chin shields, which are no larger 
than gulars; 10 maxillary teeth. 

Scales smooth, without apical pits, in 15 longitudinal rows which 
are reduced to 13 opposite the fifth ventral before the anal through 





fur 

Fig. 13. Dorsal and lateral views of holotype of Pseudorabdion eiselti, new sp. 
Actual size 8 mm. 



loss or fusion of lateral scale row 3; caudodorsal scales reduced to 4 
opposite the tenth subcaudal posterior to vent; ventrals 130, the last 
one split; anal undivided; subcaudals 12, paired. 

Total length 200 mm., tail 10 mm., head to end of parietals 7.5 
mm., diameter of eye 1.4 mm. 

Color (in alcohol) faded but evidently dark brown above and be- 
low, each dorsal scale with a light network or light apical spot; head 
dark brown above, upper lip lighter; an obscure yellowish crescent 
along lateral margin of parietals. 

Comparisons. In head scutellation eiselti resembles three Philip- 
pine species: ater (Taylor), oxycephalum (Giinther), and montanum 
Leviton and Brown. It differs from all three in having distinct su- 
praocular and postocular shields, the internasal meeting the first 
supralabials behind the nasal (indicating the shortness of the nasal 
shield), and a proportionally larger eye. The proportion of eye di- 
ameter to eye-mouth distance shown by Leviton and Brown (1959; 
fig. 5) for Pseudorabdion montanum is incorrect. The eye is much 



INGER AND LEVITON: SNAKE FROM SUMATRA 47 

too large, compared to the vertical length of the adjacent supra- 
labials, and should be reduced by one- third. The eye diameter /eye- 
mouth distance ratio is correctly portrayed for P. oxycephalum (fig. 4, 
op. cit.), which P. montanum most closely resembles. The eye diam- 
eter/eye-mouth distance ratio in eiselti is similar to that in P. longi- 
ceps (fig. 1, op. cit.). 

Pseudorabdion ater differs further from P. eiselti in having the 
frontal bordering the eye and the nasal divided. Pseudorabdion 
oxycephalum and P. montanum have higher ventral and subcaudal 
counts than eiselti. The counts for females of these species are: 
oxycephalum 144-157 and 16-17; montanum 154-161 and 21-22; eiselti 
130 and 12. Data for the Philippine species are from Leviton and 
Brown (1959). 

The only known species that may be sympatric with eiselti is 
P. longiceps (Cantor), which has been recorded from the west coast 
of Sumatra at Ayer Bangis (de Rooij, 1917), about 170 km. from the 
type locality of eiselti. It differs from eiselti in the presence of a pre- 
ocular, the separation of the internasals from the labials, and higher 
subcaudal counts (females 17-20). Both longiceps and eiselti have 
larger eyes and more maxillary teeth than their Philippine congeners 
that also lack loreal shields. 

All other species of Pseudorabdion differ from eiselti at least in 
the presence of loreals and in having the prefrontals and internasals 
separated from the labials (a direct consequence of having distinct 
loreals). One, albonuchalis (Gunther), has the frontal bordering the 
eye. Two, saravacensis (Shelf ord) and sarasinorum (Muller), have 
more maxillary teeth (18-21 and 14 respectively) than eiselti (10). 
And at least two, taylori Leviton and Brown and mcnamarae Taylor, 
have higher subcaudal counts (females 33-35 and 20-23, respectively). 
The counts are from Leviton and Brown (1959). 



REFERENCES 

Leviton, A. E., and Brown, W. C. 

1959. A review of the snakes of the genus Pseudorabdion with remarks on the 
status of the genera Agrophis and Typhlogeophis. Proc. California Acad. Sci., 
(4), 29: 475-508, 10 figs. 

de Roou, Nelly 

1917. The reptiles of the Indo-Australian Archipelago. Vol. II. Ophidia. 
xiv+334 pp., 117 figs. Leiden, E. J. Brill, Ltd.